Process of making artificial teeth



Patented Feb. 2L 19 22. 2 $H EET$-SHEET I.

J, n, M

J. tinosa.

PROCESS OF MAKING ARTIFICIAL TEETH.

APPLICATION FILED OCT- 7 1920. m.@7,4s4.,

1. E. ROSE.

} PROCESS OF MAKING ARTIFICIAL TEETH.

APPLICATION FILED cm. 1, 1920.

- Patented Feb. 21, 1922.

2 SHEETS-SHEET 2 .Josnrn ELON ROSE, or ron'rnann, oanoon.

PROCESS OF MAKTNG ARTIFICIAL TEETH.

tamer."

Specification of Letters Patent. Patented F b, 211 192% Application filed October 7, 1920. Serial No. 415,258.

, useful Improvement in Processes of Making Artificial Teeth, of which the following is a specification.

The present invention relates to artificial teeth and has to do more particularly with artificial teeth wherein a croWn of gold or other suitable material is 'provided with a facing of porcelain or like material shaped and colored to simulate a natural tooth. The invention is directed to the production of a new and durable tooth structure.

One object of the invention-is to produce an artificial tooth which shall be stron and durable while presenting a neat finish c osely simulating a natural tooth. Another object is to produce a novel structure which shall include only a crown and facing which accurately and firmly fit and engage each other. Another object is to so shape the engaging portions of the crown and facing that the latter will be firmly retained in place under all the varied conditions of service.

In carrying out my invention, I provide a crown of onemetal throughout which has a front wall comprising a central protruding portion more or less surrounded by a peripheral groove or grooves. The facing of porcelain or like material is'shaped so as to accurately fit said protruding portion and grooves and to bear against the same throughout its entire engaging surface. The process for bringing about this result includes several operations. In performing my process I first fornia crown so as to fit the prepared tooth and cut away a port on of its face. With the crown in positlon upon the prepared tooth I then press warm wax into the opening against the tooth. A facing of porcelain or like material is then pressed against th soft wax and the surplus wax trimmed 0d. The crown, wax and facing may then be removed from the tooth. After the facing is removed from the wax, a mold is made to fit the assembled crown and. wax, the crown and wax serving as a pattern. Then the wax is removed from the crown by heating the mold. Then molten gold or other metalis poured into the mold and the gold occupies the space formerly occupled by the wax. As a result theopen face of the crown is closed by a metal wall WhICh accurately fits both the tooth and facmg and to which the facing may be readily attached by cement. The facing, itself, is made from a baked porcelain form by grinding 1t to the desired shape.

t will be seen that in carrying out my invention I am enabled to produce a crown having a porcelain or like facing which may be used on vital teeth. It will also be seen that the metal wall between the facing and the prepared tooth conforms exactly to the irregularities of both the tooth and the facing and .thus provides an accurate fit which enables the parts to be readily secured together by cement. Furthermore, the protruding portion of the front wall of the crown together with the peripheral groove and the cooperating surfaces on the facing give the assembled structure a strong and retentive form which greatly strengthens the crown and thereby increases its life and durability. Not only is this true, but by the method I employ, the cuttin away of the tooth in preparingit is red bced to a minimum, as it does not need to be shaped so as to fit a particular wall. The construction is such also that the crown may be used as an'abutment or anchor for a bridge. There are other features and advantages which will be more particularly pointed out hereinafter'while others need not be mentioned since they will be at once apparent to dentists and others skilled in this art.

The invention in its various-features and aspects will be more fully understood upon re ference' to the following detailed description taken in connection with the accompanying drawing, and the scope of the invention will be particularly pointed out in the appended claims.

In said drawing, Fig. 1 is.-a perspective view of an artificial tooth or crown constructed in accordance with the present in-' vention; Fig. 2 is a vertical section of the crown showing the front cut awayso as to provide an open face; Fig. 3 is a similar view of the same crown placed upon the prepared tooth and the open face filled with wax; Fig. 4: 1s a similar view showing the facing Fpressed up lnto en agement wlth the wax; 1g. .5 1s a wow of t e crown and wax,

with the facing removed, secured to the sprue wire in the crucible former; Fig. 6 is a sectional view of a ring mold filled with investment material and the wax burned out, all ready for the pouring of the metal; Fig. 7 is sectionalview of the finished crown removed from the mold, its open front now being closed by a metal wall; Fig. 8 is a similar view 'of the finished tooth showing the facing secured to the outer surface of the metal wall; Fig. 9 is perspective view of the finished crown with the facing removed; Fig. 10 is a section through the crown in position upon the prepared tooth, the section being taken on a plane indicated by the line 1010 of Fig. 8; Fig. 11 is a perspective view of the crownwhen in the condition shown in Fig. 2; Fig. 12 is a perspective view of a modified tooth, showing a crown and facing of somewhat different shape; Fig. 13 is a vertical section of the crown of said modified tooth, showing the front of the crown cut away so as to provide the open face; Fig. 14 is a perspective view of the same crown after the metal has been poured to form the front wall; Fig. 15 is a section through the finished modified crown in position upon the prepared tooth, the section being taken on a plane indicated by the line 1515 of Fig. 13. Throughout these views like characters referto like parts.

Referring to the drawing in detail, 9 designates a crown of gold or other suitable material which may be made in any preferred way. According to one method of forming a crown the distance around the prepared tooth 10 is measured at the gum line by a fine wire and a strip of gold is then out according to the length of this wire and its ends brought together and soldered or otherwise secured together so as to form a band. This is then'placed upon the tooth and trimmed, festooned and otherwise shaped so as to bring about the desired fit. Obviously other ways of producing the crown may be employed. When the crown is produced its face is cut away so as to provide an opening 11. -When the open faced crown is upon the tooth this opening is positioned so as to ex ose the labial face of the prepared tooth. hile the crown is in this position upon the tooth a quantity of warm and plastic wax 12 is placed over thetooth at the point where the opening is and the opening is well filled with the wax. Then the facing 13 which has previously been prepared is pressed against the soft wax until the facing has been brought into its desired position, and the surpluswax is trimmed away. The crown, wax and facing are then removed as a unit from the tooth and a mold is prepared. This mold consists of two parts composed of the usual investmentv material employed by dentists for this class of work. One part of the mold,

designated 14, is made by filling the interior.

of the crown while the wax and facing are in position, with the investment material and allowing it to harden or set. This portion of the mold then takes the place of the prepared tooth and has the same shape as the tooth. At this stage the facing-1s removed from the crown. The other portion of the mold, designated 15, is formed by enclosing the form 14 with the crown 9 and the wax 12 upon it, with investment material in a suitable receptacle. In the case illustrated, the receptacle comprises a ring 16 having a crucible former 17 provided with a central opening for a sprue 19. The form 14 with the crown and wax upon it is then attached to the end of the sprue 19 by the wax. Investment material is applied to the crown upon the sprue in the usual manner, and then the ring 16 is placed on the crucible former, over the crown, and filled with.

investment. This leaves all the parts carried by the sprue completely surrounded by the investment material 15. When the investment material has set, then the crucible former 17 and the sprue 19 are removed, leaving the sprue canal 20. The ring and its contents are then heated and the wax melted and driven off, leaving the void 21 which is to be filled with molten metal. When pouring theimetal, the ring and its contents, as illustrated in Fig. 6, is set on the exhaust stand 22 of a suitable exhausting machine. The exhausting air passes through ,the pores of'the investment material and causes the molten metal, as it is poured, to enter all portions of the void 21. Although I have described the casting operation as one'using an exhaust, other casting methods may be employed. When the metal is poured in in this way it fuses with the metalof the crown and provides a solid metal wall 23. This wall closes the opening in the face of the crown 9 and both its front surface and its rear surface have the same shape as did the wax. the front face of the wall 23 hasa surface which closely and accurately fits the rear wall of the.facing 13. Similarly the rear face of the wall 23 accurately fits the adjacent surface of the prepared tooth 10. It will be noted also that the front wall 23 comprises a central protruding portion bounded by peripheral grooves 24. These grooves serve to hold the facing upon the tooth with greater certainty, and the walls of the groove, especially that near the incisal edge of the tooth, serve to transmit the strain of impact upon the facing 13 to the crown 9. In this form of the invention, the overlap of the facing about the incisal edge of the crown greatly improves the esthetic appearance of the finished structure. The twofacings are to be used for different Consequently metal forming the wall 23 has cooled, the crown with its new wall may be'removed from the mold. It is then a simple matter to afiix the crown to the prepared tooth by cement. In like manner the facing 13 may be secured to the wall 23 by cement.

As before noted I make the facing 13 out of ready-baked porcelain by grinding the same to the desired shape. It will be obvious that crowns of different t pes of manufacture may be employed. he facings may also be made in different ways and they may also be variously shaped. In any event they should ordinarily be made to cover all the metal of the crown as the tooth is viewed when looking toward the labial surface. In the structure which I have .heretofore described, the facing extends over 12 to 15 inclusive, wherein the crown 9' is provided with an opening 11 which extends onlyto the incisal edge 25' of the crown. When the crown is completed by the addition of cast wall 23',- that wall does not go beyond or include the incisal edge but is of the same length and outline as the opening 11'. In this structure the lower groove 24', or, if

' you please, the incisal portion of the peripheral groove 24, has a wall 26 which receives the pressure applied to the incisal edge of the facing 13'. There are, as before, the verti' cal portions of the peripheral groove 24' into which the vertical portions of the pe ripheral ribs of the facing 13' accurately fit.

. Thesegrooves in both illustrated forms of the invention co-operate with the corresponding projections or ribs upon the facing to firmly hold the latter in place when subjected to the strains and shocks due to the use of the tooth. In the modified form the tion the strain is taken up more directly by others sk1 the portion of the wall 23 at the incisal edge 1 25. Obviously such changes as here disclosed and others of like character may be made without departing from the spirit and scope of'my invention. Obviously, too, the configuration of the facing may be greatly varied. The size of the opening may also be varied. 'Otherchanges and alterations will suggest themselves to dentists and wish to be limited to the precise details disappended claims all the modifications and variations which properly come withivthe scope of the invention.

led in this art. I therefore do not types of teeth, long and short. When the I What I claim as new and desire to secure toothwhich includes the operations of forming a'crown with an open face, closing the open face with wax, shaping the front of the wax to receive a facing, casting a wall for the crown in place of the wax, and securing the facing to the front of said wall.

2. The process of preparing an artificial tooth which includes the operations of forming a crown with an open face, closing the open face with wax, shaping the front of the wax to receive a facing, shaping the rear of the wax to fit the tooth, casting a wall for the crown in place of the wax, and securing the facing to the front of said wall.

3. The process of preparing an artificial tooth which includesthe operations of forming a crown with an open face, closing the open face'with wax, shaping the front of the wax to receive a facing, preparing a mold to fit the assembled crown and wax, melting out the wax, and casting a wall for the crown in place of the wax.-

4. The process of preparing an artificial tooth which includes the operations of form ing an open faced crown and positioning the same upon a prepared tooth, closing the open .face by wax pressed against the tooth, pressing thefacing into the open face against the wax, casting a wall in place of the wax, and finally cementing the crown to the tooth and the facing to said wall. i

5. The process of preparihg an artificial tooth which includes the operations of forming an open faced crown and positioning the same upon a prepared tooth, closing the open face by wax pressed against the tooth, pressing a facing into the open face against the wax, preparing a mold to fit the assembled crown and wax, melting out the wax, casting a wall for the crown in place of the wax, and finally cementing the crown to the tooth and the facing to said wall.

6.- The process of preparing an artificial tooth-which includes the operations of forming an open faced crown, positionin wax in the open face to close the same, an casting a wall for the'crown 1n place-of the wax. 7. The process of preparing an artificial tooth which includes the operations of forming an open faced crown, positioning wax in the open face to close the same, preparing a mold to fit the assembled crown and wax, melting out the wax, and casting a wall for the crown in place of the wax. r

In testimony whereof, I hereunto subscribe my name this 30 day of September, A. -D.-1920. 

